Waterproof felted sheet



Patented Oct. 13, 1931 UNITED STATES PATENT OFFICE LESTER KIRSCHBBAUN,

PANY, OF BOSTON,

OF LEONIA, NEW JERSEY, ASSIGNOR TO THE FLINTKOTE COM- ]!TASSACHUSETTS, ACORPORATION OF MASSACHUSETTS WATERPROOF FELTED SHEET No Drawing.Original application filed May 13, 1929, Serial No. 862,877. Dividedfiled May 6, .1930.

This application is a division of my coppnding application, Serial No.362,877, filed ay 13, 1929. This invention relates to waterproof feltedfibrous sheets wherein the fibrous constituents are combined with theWaterproofing ingredients prior to the felting operation. Moreparticularly the invention is concerned with Waterproof felted sheetswherein normally non-fluid and adhesive bitumens are employed as thewaterproofing ingredients, these materials, when properly associatedwith the fibers, providing very efi'ective barrlers against the entranceor permeation of water into the sheet.

In order to combine normally adhesive Waterproofing material, such asasphalt or the like, with fibers prior to a felting operation forforming the several constituents into felted sheets, the waterproofingmaterial must first be rendered relatively non-adhesive in order toprevent gumming up of the blankets and other parts of the paper machine.Methods of thus converting the relatively adhesive waterproofingmaterial, as for example, asphalt, to a relatively non-adhesivecondition, and sheeting a mixture thereof with fibers on a paper makingmachine, are described in Patent No. 1,536,399, issued to me May 5,1925. In accordance with said patent, the asphalt or other bituminous orpitchy binder, is brought to a relatively non-adhesive state, as forexample, by emulsifying the same in an aqueous medium comprising anemulsifying agent and water, whereupon the emulsified bituminous binderis mixed with fibrous pulp and amalgamated uniformly therewith, as forinstance, in the beater or in the stuff chest, and is then run ofl inthe usual manner on the paper making machine. The non-adhesive characterof the emulsified bitumen enables the paper forming operation to becarried on without gumming the blankets or other parts of the machine,due to l the fact that this characteristic prevails as long as theemulsion is stable and highly resistant to pressure during the sheetforming operation, which condition, as soon as substantially completeelimination of Water from the sheet occurs (e. g., on the driers),permits and this application Serial No. 450,322.

the dispersed bitumen particles to coalesce and resume their adhesivecharacter, resultmg in the union thereof with and about the fibers so asto produce a highly water-resistant sheet.

The present invention has for its chief object the provision of awaterproof felted sheet quite similar to the product produced by theprocess above referred to and more particularly set forth in the saidpatent. According to the present invention, the transformation of theWaterproofing material to a condition as above described whereby torender possible the admixture thereof with fibers and the fabrication ofsuch mixture on a paper machine. is achieved in the beaters usuallyemployed to reduce the fibrous material to pulpy condition suitable forpassage over the paper forming mechanism equivalent agitating mechanismtransforms the binder to a condition in which it is uniformlydistributed therethrough. I have further found that most fibers that areemployed commercially in paper manufacture possess colloidal propertieswhen beaten out for a substantial length of time, and that thiscolloidal nature of the pulp can be utilized as a means for assisting inthe dissemination of bituminous material such as asphalt throughout thepulp stock and for assisting in converting the same to conditionpermitting the same to be manipulated successfully over the papermachine. The efliciency of the fibrous pulp in this regard may befurther assisted by means of the addition of suitable protectivecolloids, and in practical operation of the process herein described,suitable proportions of protective colloid are employed to insureagainst any tendency of the bitumen to adhere to the paper makinginstrumentalities.

In carrying out the invention, the desired fibrous material isintroduced into a beater with sufiicient quantities of water to permitcirculation therein, and while the mass of fibers is being beatentherein. or after it has been beaten out to a sufiicient extent. thebituminous binder, as for example, asphalt of 100 to 200 F. meltingpoint in heat liquefied state, is fed gradually to the beater while sothat the beating or.

the stock is approximately at or somewhat above the melting point of theasphalt and the operation of the beater is continued for a sufficienttime to effect uniform distribution of the bitumen throughout the pulp.I have found that the pulpy fibrous mass is capable, under the continuedaction of the beater roll, of acting upon the heat liquefied bitumen toproduce a state of intimate association of the bitumen with the fibers,in the aqueous content of the mass.

In some instances it may be found necessary or desirable to assist inthe distribution of the bitumen through the pulpy mass by incorporatingtherein, either before the introduction of the bitumen or simultaneouslytherewith, suitable quantities of colloidal material. as for example.colloidal clay, finely powdered mineral oxides, gelatine, tannic acidand starch. The amount of colloidal material thus incorporated will beregulated in accordance with the hardness of bitumen used in theprocess. (the latter depending largely upon the hardness desired in thefinal product) the amount of bitumen to be combined with the pulp, thecharacter of the fibrous pulp, particularly its own ability to effectsubdivision of the bitumen and cause the latter to assume a relativelynon-adhesive condition. Thus, where the proportions of ingredients inthe beater are such that the bitumen comprises 20 to thereof on the dryweight basis, and with Mexican asphalt of a melting point of 150 to 170F., the transformation of the asphalt to a non-adhesive condition may beassisted. if necessary, by the addition of 1 to 5% of colloidal clay, onthe basis of weight of asphalt. The protective colloid serves also toensure against sticking of the asphalt to the blankets or other parts ofthe machine.

In actual practice, even where the bitumen may be distributed in thepulp as above described, small amounts of protective colloid should beincorporated in the mass in order to increase the stability of thedispersed material against the pressure and mechanical action to whichit is subjected in passing over the paper machine and to insure againstany tendency of the dispersed material to adhere to the various parts ofthe machine. For this purpose, the protective colloid in suitablequantities may be added to the beaten mass of pulp and bitumen after thelatter has been fairly completely distributed through the pulp by thebeating action in the presence of the pulp, or, if desired, the colloidmay be introduced before or simultaneously with the introduction of thebitumen. In any event, however, the quantities of protective colloidwill be governed by the/factors above noted and by theinherent rela-.

tive stability of the dispersion effected by means of the fibrous pulpitself. Generally, however, with materials and proportions as abovestated, 2 to 8% of clay, bentonite or similar colloid will suflice tomake the operatiofigzaetical from all points of view.

r the bitumen combined with the pulp in the beater has been converted tothe requisite nonadhesive condition and stabilized, if necessary, in themanner described, the mixture is in readiness for the sheetingoperation.

erably in the presence of sodium, or other alkali silicate, may be addedat any convenient stage prior to the passage of the mixture over theforming screen. The alum should be employed in suflicient quantities toflocculate or precipita e any unattached bitumen onto the fiber, so thatthe water will run clear from the stock during formation. The action ofthe alum upon the soluble silicate or other reacting substances presentproduces a voluminous bulky precipitate, which acts as a furtherprotective film interposing itself between the bitumen and anycontacting parts of the apparatus. In practice, 3% silicate and 5% alumwill be suflicient to produce the result and bring the stock to anacidic condition. The wet web of felted fibrous material with itscontained bituminous binder is capable of passing over the various partsof the paper machine, by virtue of the fact that the relativelynonadhesive condition of the stock is preserved until the water issubstantially completely removed. As the last portions of water areremoved in the passage of the sheet over the driers, the bitumen regainsits normally adhesive character and fuses to coalesce and form more orless continuous films about the fibers.

While I have described the operation as applied to a single web, it isobvious that the features of the invention may be utilized in connectionwith one or more cylinders of a multi-cylinder machine. Thus, theadhesive binder may be combined with fibrous stock of certain of theplies (for example, the inner ply or plies), while the fibrous stock ofthe other (outer) plies may be left free of the bituminous binder. Theinvention is also adaptable for wet-board machine operation, in whichcase the bituminous binder rendered nonadhesive as above described, iscontained in the fibrous stock of the cylinder mould, so that as thesuccessive layers are transferred from the blankets to the make-up roll,the composite structur will be permeated throughout with the binder inrelatively nonadhesive condition.

The composition may be employed for other purposes besides producing afibrous sheet on the paper machine. In the form of a fibrated emulsionit may be used alone as a. plastic waterproof covering, or it may bemixed with mineral aggregate to produce a fibrated floor mastic. For thelatter purposes, softer asphalt is preferred which is coalescable atnormal atmospheric temperatures. Such a fibrated dispersion may comprise10% of wood pulp, 40% of asphalt and 50% of water. When used forflooring it will be mixed with mineral aggregate and in proportions that10-15% of bitumen will be present in the final mixture.

Having thus described my invention, What I claim is: v

1. A fibrous paper making stock comprising a heat fusible waterproofbinder and fibrous pulp in an aqueous vehicle, the binder beingsubstantially uniformly distributed through the pulp and held indispersed condition by constituents of the pulp functioning asdispersive media, the binder constitutin the dispersed phase and beingrendered su ficiently non-adhesive to prevent sticking thereof to thepaper making instrumentalities.

2. A fibrous paper making stock comprising a heat fusible waterproof.binder and fibrous pulp in an aqueous vehicle, the binder beingsubstantially uniformly distributed 7 through the pulp and held indispersed condition by constituents of the pulp flmctioning asdispersive media, the binder constituting the dispersed phase and beingrendered sufficiently non-adhesive to prevent sticking thereof to papermaking instrumentalities, said fibrous composition also containing aprotective colloid of such character and quantity 'as to stabilize thebinder.

3. A fibrous paper making stock comprising a heat fusible waterproofbinder and fibrous pulp in an aqueous vehicle, the binder beingsubstantially uniformly distributed through the pulp and held indispersed condition by constituents of the pulp functioning asdispersive media, the binder constituting the dispersedphase and beingrendered sufficiently non-adhesive to prevent sticking thereof to papermaking instrumentalities, said aqueous composition also containing amineral powdered protective colloid of such character and quantity as tostabilize the binder. I

4. A fibrous paper making stock comprising a heat fusible waterproofbinder and fibrous pulp in an aqueous vehicle, the binder beingsubstantially uniformly distributed through the pulp and held indispersed condition by constituents of the pulp functioning asdispersive media, the binder constituting iii) the dispersed phase andbeing rendered sufficiently non-adhesive to' prevent sticking thereof topaper making instrumentalities, said aqueous composition also containinga clay-like'protective colloid in sufficient quantity to'stabilize thebinder.

.5, An aqueous composition comprising a heat fusible waterproof binderand fibrous pulp in an aqueous vehicle, the binder being substantiallyuniformly distributed through the pulp and held in dispersed conditionby constituents of the pulp functioning as dispersive media, the binderconstituting the dispersed phase and being rendered sufiicient- 1ynon-adhesive to prevent sticking thereof to paper makinginstrumentalities, said blnder bemg clotted or deposited on the fibers msuch a manner as to provide a freely feltable furnish.

S. A stock capable of being felted comprismgfibrous pulp and a heatfusible waterproof blndcr in an aqueous vehicle, the bin der beingsubstantially uniformly distributed through the pulp and renderednon-adhesive to prevent stickmg thereof to paper makinginstrumentalities by constituents of the pulp functioning as dispersivemedia.

7. A stock capable of being felted comprising fibrous pulp and a fusiblewater roof binder in an aqueous vehicle, the binder eing substantiallyuniformly distributed through the pulp and rendered suflicientl non-acthesive to prevent sticking'thereof to paper making instrumentalities byconstituents of the pulp functioning as dispersive media, and aprotective colloid of such character and in such quantity as tostabilize the binder.

8. A stock capable of being felted comprising fibrous pulp and a heatfusible waterproof binder in an aqueous vehicle, the binder beingsubstantially uniformly distributed through the pulp and renderedsufliciently non-adhesive to prevent sticking thereof to paper makinginstrumentalities by constituents of .the pump functioning as dispersivemedia, said binder being deposited or clotted on the fibers in such amanner as to provide a freely feltable furrii sh.

9. A fibrous paper making stock comprising an aqueous dispersion of afusible waterproof binder and fibrous ulp in aqueous medium, the binderbeing su stanti ally uniformlv distributed through the pulp in the formof discrete particles and held in said condition bv the pulpyconstitutents functioning as dispersive media.

10. A fibrous product comprising wet pulp intimately associated with awaterproofing binder, the binder being distributed in the form ofdiscrete particles throughout the stock and the constituents of thestock serv-' ing to substantially prevent the aggregation of the binderparticles in the wet pulp and the binder having been converted in theform of discrete particles throughout the stock and in the presencethereof.

11. A fibrous product consisting of wet pulp intimately associated witha waterproofing hinder, the binder being distributed in the presence ofthe pulp and in the form of discrete particles and prevented fromsubstantial aggregation in the wet pulp and the binder having beenconverted in the form of discrete particles throughout the stock and inthe presence thereof.

%2. A fibrous product consisting of wet u iilg binder, the binder beingdistributed in the presence of the pulp and in the form of discreteparticles and prevented from substantial aggregation in the wet pulp bythe cellulosic constituents thereof acting conjointly with an additionalprotective colloid and the binder having been converted in the formofdiscrete particles throughout the stock and in the presence thereof.

13. An aqueous stock comprising wet fibers intimately associated with aheat plastic binder, the binder being distributed in the form ofdiscrete particles with the cellulosic constituents of the stock tendingto prevent substantial aggregation of the discrete particles wherebysaid stock with its associated binder is capable of being felted on apaper making machine without gumming the instrumentalities and thebinder having been converted in the form of discrete particlesthroughout the stock and in the presence thereof.

14. A fibrous product ,consisting of wet pulp intimately associated witha heat plastic binder having a melting point of between 100 and 200 F.,the binder being distributed in the form of discrete particlesthroughout the stock and the constituents of the stock serving tosubstantially prevent the aggregation of the binder particles in the wetpulp and the binder having been converted in theform of discreteparticles throughout the stock and in the presence thereof.

15. A fibrous product consisting of wet pulp intimately associated witha water proof binder, the binder having been converted into discreteparticles in the presence of the pulp and being prevented fromsubstantial aggregation by the wet pulp.

16. A fibrous product consisting of wet pulp intimately associated witha heat fusible water proof binder, the binder having been converted intodiscrete particles in the pres- V ence of the pulp and held in dispersedcondition and prevented from substantial aggregation by the wet pulp.

In testimony whereof I afiix my signature.

LESTER KIRSCHBRAUN.

intimately associated with a waterproof-

